The Infiltration into the HYDRA Herefordshire Facility began as an unsanctioned S.H.I.E.L.D. mission orchestrated by the combined forces of Leo Fitz, Jemma Simmons, and Yo-Yo Rodriguez in an attempt to destroy the Particle Infusion Chamber. That particular mission failed due to Ruby Hale's involvement; the second phase, led by Quake, became rescuing the three from the clutches of Ruby and Werner von Strucker, with the aid of General Hale, Ruby's mother. As Quake's team arrived, Ruby infused herself with Gravitonium, resulting in her obtaining gravitational powers she could not control. The mission ended with Rodriguez killing Ruby and S.H.I.E.L.D. obtaining the Particle Infusion Chamber and remainder of the Gravitonium, while a distraught Hale escaped.
Shortly following their return from the future, the S.H.I.E.L.D. agents were confronted by Hale who was determined to capture the S.H.I.E.L.D. agents at any cost. This grew suspicion among the S.H.I.E.L.D. agents who decided to capture Hale in order to uncover her agenda. Although they initially succeeded, it turned out that Hale had actually lured S.H.I.E.L.D. into a trap and Phil Coulson ended up captured instead, and learned from Hale that HYDRA had returned under her leadership.
The other S.H.I.E.L.D. agents struggled to find a way to rescue Coulson. Moreover, they had to face another challenger as Leo Fitz experienced a major psychic split which led to him capturing Daisy Johnson to forcefully remove her Inhuman Control Device. As a result, Fitz was locked up in the Lighthouse, but Melinda May later came to him to have his insights regarding Hale's possible whereabouts. Fitz managed to identify potential locations for a weapon Hale might be after, but Johnson refused to let him out to further investigate.
Therefore, once Johnson and May had left to find Robin Hinton for more answers, Jemma Simmons, assisted by Yo-Yo Rodriguez, tricked Alphonso Mackenzie into releasing Fitz. Fitz, Simmons, and Rodriguez then decided to conduct their own search for Coulson, taking a Quinjet out of the Lighthouse.
Meanwhile, Hale's daughter Ruby worried about the fight that Hale would select someone else to become the Destroyer of Worlds, although Ruby had been specifically engineered for this project. Supported by Werner von Strucker after her failure to apprehend Coulson and Glenn Talbot when they escaped from the HYDRA Preparatory Academy, Ruby rebelled against her mother and decided to find and use the Particle Infusion Chamber without Hale's consent.
Leo Fitz, Jemma Simmons and Yo-Yo Rodriguez arrived at their first location, Herefordshire, England where the HYDRA secret weapon could be. They jumped out of the Quinjet and proceeded to the HYDRA facility. They then witnessed an incoming truck arriving which turned out to be Anton Ivanov leading a fleet of Sleeper Mechs, securing the facility. They further made their way into the facility where they found Ivanov guarding the chamber. In order to distract him, Fitz set off some explosives from outside. As they proceeded, Simmons discovered a secret entrance through a wall that contained the chamber. Once they got into the secret room, the S.H.I.E.L.D. agents began to destroy the equipment in the hope that it would not be able to work.
Once they had destroyed a component for the Particle Infusion Chamber, the S.H.I.E.L.D. agents were alerted by a group of Sleeper Mechs trying to break in. They attempted to disarm them, but when Yo-Yo Rodriguez used her powers, her arms overloaded her nervous system, causing great pain and thus preventing her from resorting to her powers. As a result, Leo Fitz and Jemma Simmons decided to stay and try to defeat the Mechs while Rodriguez went to call for backup.
Once Rodriguez left, Fitz and Simmons commenced in a shootout between themselves and the Mechs. They managed to fend off several androids, but would soon become overwhelmed as more and more kept coming. As they started to run out of ammunition and Simmons' gun got jammed, they realized that they would not be able to fight back any longer. As the Mechs approached the couple, they held each other in their potential final moments.
Yo-Yo vs. the Superior
Meanwhile, as Yo-Yo Rodriguez went back to the Quinjet, she was stopped by Anton Ivanov and the two began to fight. As the fight went on and got more intense, Ivanov commented on new robotic limbs while stating how he was superior to her. Nevertheless, Rodriguez managed to subdue Ivanov, cutting open his chest and pushing him out of the window. Due to this LMD having Ivanov's actual head, he was killed from the impact of the fall. This then caused the entire army of Sleeper Mechs to shutdown as Ivanov was controlling all of them, which saved the lives of Leo Fitz and Jemma Simmons. Rodriguez then proceeded to call for backup.
However, Ruby Hale and Werner von Strucker then arrived at the HYDRA Herefordshire Facility, where they captured Leo Fitz and Jemma Simmons and discovered that they had destroyed the components for the Particle Infusion Chamber. They then threatened Simmons, ordering Fitz to repair the component so that Hale could be infused with the Gravitonium they had brought along and become the "Destroyer of Worlds." While Fitz worked on the chamber, Simmons was strapped up to a chair and Hale playfully threw her Chakram next to her. Von Strucker briefly left to reactivate the Sleeper Mechs before returning.
Fitz eventually managed to convince Hale to untie Simmons so she could help him to repair the chamber. They resolved on working as slowly as they could, waiting for backup called by Yo-Yo Rodriguez, who barely defeated an android attacking her. As von Strucker and Hale grew more and more annoyed by their slow work, Fitz and Simmons announced that they were done. However, von Strucker examined the supposedly repaired component and figured out that it was reversed. Convinced that the S.H.I.E.L.D. agents were trying to fool them, Hale violently attacked Fitz and beat him up, threatening to kill Simmons the next time he made a mistake.
Fitz and Simmons resumed their work and properly repaired the component for the infusion chamber. However, they also tried to warn von Strucker and Hale about the dangers of using the Gravitonium, although they elected to ignore these warnings. Von Strucker then prepared both the Gravitonium and the chamber for the infusion. Once it was finished, Hale entered the Chamber and gave von Strucker her Chakram. Von Strucker then activated the infusion process, but it turned out to be incredibly painful and Hale began screaming in agony as she was being infused by the Gravitonium.
Destroyer of Worlds
Distressed by Ruby Hale's pain, Werner von Strucker confronted Leo Fitz and Jemma Simmons, blaming them for what he considered a failure. However, General Hale, who had allied with S.H.I.E.L.D. agents Quake and Melinda May in an attempt to stop Ruby, arrived and stated that the Gravitonium was to be blamed. Fitz ended the infusion process and all of them waited as the Particle Infusion Chamber opened with an unconscious Ruby in it.
Ruby eventually regained consciousness. As she had been infused with 8% of the available Gravitonium, she began displaying gravity-related abilities and levitated out of the chamber before falling back onto the ground. As von Strucker attempted to comfort her, pushing back Hale, Ruby begged him to help her, but she accidentally crushed von Strucker's skull with her uncontrolled gravity manipulation abilities, thus killing him.
As Ruby was progressively driven insane by the voices of Ian Quinn and Franklin Hall arguing in her head, she violently attacked Fitz and Simmons, pinning them against a wall. Both Hale and Quake attempted to calm down Ruby, who eventually released Fitz and Simmons. Quake ordered Melinda May to take them to safety. On their way out, they encountered Yo-Yo Rodriguez, who arrived in the chamber room where a despaired Ruby screamed in pain and sadness, attacking Quake despite her mother's plea.
Although Hale and Quake ultimately seemed to succeed in their endeavor to appease Ruby, Rodriguez recognized the young woman as the one who had sliced off her arms during the Infiltration into St. Louis Aerospace Facility. Despite Quake ordering her to stand down, Rodriguez was filled with a desire for revenge. She used her superhuman speed to take Ruby's Chakram put on a nearby table and then slit Ruby's throat with the weapon. Ruby's body collapsed on the floor before briefly levitating and unleashing a powerful burst that knocked everyone present unconscious. When the S.H.I.E.L.D. agents regained consciousness, they discovered that Hale had escaped.
The murder of Ruby Hale caused a strong argument between the different S.H.I.E.L.D. agents. While Melinda May and Phil Coulson remained pretty neutral in the debate, both Daisy Johnson and Alphonso Mackenzie heavily criticized Yo-Yo Rodriguez for her decision, calling it unworthy of what S.H.I.E.L.D. stood for. Leo Fitz and Jemma Simmons, who felt sorry for the deed, still considered that Rodriguez had made a difficult choice which had probably saved the world from a dangerous threat. This caused the friendships between the agents to be heavily affected.
Nothing Else to Lose
Despaired by the loss of her only daughter, Hale reached out to Confederacy member Qovas. She informed him that S.H.I.E.L.D. had confiscated the Gravitonium in the Lighthouse. As Qovas asked her whether she would let him kill the S.H.I.E.L.D. agents to reclaim the Gravitonium, Hale replied that she had no reason to stop him. As a result, Qovas initiated the Siege of the Lighthouse in order to retrieve the Gravitonium he wanted. However, due to S.H.I.E.L.D. having also reclaimed the Particle Infusion Chamber, the Remorath would lose the battle due to Glenn Talbot infusing himself with the Gravitonium in an attempt to make up for his mistakes.